The ITS-90 recommends thatwater cells be made from water with substantially the isotopic composi-tion of ocean water.Ӕ Research hasshown that TPW errors associated with isotopic composition can be as large as 0.00025 C. The uncertaintycontribution from VSMOW errors inHart cells is less than б 0.000007 C. ThatВs seven micro-Kelvin!Hart offers two options for verify-ing the isotopic composition of any purchased water cell, both at nomi-nal costs. We can submit to a testinglaboratory a sample of water taken from your own cell ( after it was com-pletely manufactured, so you get avalid comparison)...

5901A-G TPW Cell, 12 mm ID with handle, glass shell 5901A-Q TPW Cell, 12 mm ID with handle, quartz shell > 5901C-G TPW Cell, 13.6 mm ID, glass shell 5901C-Q TPW Cell, 14.4 mm ID, quartz shell 5901D-G TPW Cell, 12 mm ID, glass shell > Fluke Corporation, Hart Scientific Division 799 E Utah Valley DriveAmerican Fork, UT 84003 5901D-Q TPW Cell, 12 mm ID, quartz shell 5901B-G TPW Cell, mini, glass shell > Fluke Europe B.V., Hart Scientific Division 7312 TPW Maintenance Bath > P.O. Box 1186, 5602 BD Eindhoven, The Netherlands 9210 TPW (5901B-G) Maintenance Apparatus > For more information call: Web...